Flavonoids are the main medicinal ingredients in Camellia nitidissima, but the regulatory mechanism of flavonoid biosynthesis in flowers is unclear; therefore, the flavonoids in C. nitidissima have not been effectively used. The present study performed full-length transcriptome sequencing of C. nitidissima flower. Furthermore, the reported RNA-sequencing data of C. nitidissima petals were reanalyzed using the full-length transcriptome as a reference, and the regulatory mechanism of flavonoid synthesis in petals was elucidated. The analysis identified 43,350 isoforms annotated in non-redundant protein (Nr), Kyoto Encyclopedia of Genes and Genomes (KEGG), EuKaryotic Orthologous Groups (KOG), and Swiss-Prot databases, among which 34,602 aligned to Camellia sinensis genes. A total of 11,857 differentially expressed genes (DEGs), including 112 related to flavonoid synthesis, were identified by pairwise comparison. Subsequently, analysis of the phylogeny and the conserved motifs of R2R3-MYB using the proteins sequences identified three R2R3-MYB transcription factors that regulated flavonoid biosynthesis. Weighted gene co-expression network analysis (WGCNA) identified phenylalanine ammonia-lyase (PAL) and 4-coumarate: CoA ligase(4CL) as the hub genes and showed that bHLH79 interacted with PAL. Finally, validated the expression of seven DEGs involved in flavonoid biosynthesis using real-time quantitative PCR (qRT-PCR). Thus, the present study generated and used the full-length transcriptome as the reference to analyze the transcriptome of petals and proposed a possible regulatory mechanism of flavonoid synthesis in C. nitidissima. The study's findings unravel the genetic mechanisms underlying flavonoid synthesis and suggest candidate genes for the genetic improvement of C. nitidissima.

The mitochondrial genome of Camellia nitidissima was sequenced by Illumina and Pacbio sequencing. The results of sequences showed that a total length was 949,915 bp, and the GC content was 45.7% in assembled mitochondrial genome of C. nitidissima. 71 unigenes had been found, including 36 coding proteins and 35 non-coding proteins. Subsequently, the phylogenetic tree was built on 24 plants with the maximum-likelihood method, which had high bootstrap value and fited to the angiosperm phylogeny group classification (APG IV). The study's findings unravel the taxonomic status of C. nitidissima and benefit the evolution study.

Psychotria asiatica is a typical traditional medicinal plant. Herein, we acquired and characterized the complete chloroplast (cp) genome sequence of P. asiatica to provide genomic resources for conservation genetics and phylogenetic studies of P. asiatica. The cp genome of P. asiatica is 154,652 bp in length and consists of a large single-copy (LSC) region with 85,106 bp, a small single-copy (SSC) region with 17,960 bp, and two inverted repeat regions (IRs) with 25,793 bp. The cp genome of P. asiatica comprises 127 genes, including 82 protein-coding genes, 37 tRNA genes, and eight rRNA genes. The phylogenetic result confirmed that P. asiatica was closely related to Psychotria kirkii within the Rubiaceae.

Picrasma quassioides is a member of the Simaroubaceae family and is widely used as a medicinal plant. In this study, we sequenced and assembled the complete chloroplast genome of P. quassioides. The chloroplast genome is 160,015 bp in length, with a large single-copy region of 87,136 bp, a small single-copy region of 18,069 bp, and a pair of inverted repeat regions of 27,405 bp. It contains a total of 110 unique genes, including 77 protein-coding genes, 29 tRNA genes, and 4 rRNA genes. Phylogenetic analysis showed that P. quassioides clustered well with Simaroubaceae plants, Eurycoma longifolia, Leitneria floridana, and Ailanthus latissimus.

Piper sarmentosum Roxb. (Piperaceae) is a traditional medicinal herb native to Southeast Asia. The complete genome of P. sarmentosum was sequenced and characterized in this study with the aim of providing genomic resources for the evolution and molecular breeding of P. sarmentosum. It has a typical quadripartite structure, with a large single-copy (LSC) region of 88,979 bp, a small single-copy (SSC) region of 18,274 bp, and two copies of 27,068 bp inverted-repeat regions (IRa and IRb). A total of 130 genes were annotated, comprising 85 protein-coding genes (PCGs), 8 ribosomal RNA (rRNA) genes, and 37 transfer RNA (tRNA) genes. The phylogenetic tree showed that P. sarmentosum in the current study is closely related to Piper longum.